1. Field of the Invention
The present invention relates to a breaker and, more particularly, to a full-drain type vacuum breaker.
2. Description of the Related Art
A conventional automatic draining back flow preventer comprises a casing including a first tubular part, a second tubular part and a third tubular part which are made individually. The first tubular part, the second tubular part and the third tubular part are connected by internal threads and external threads. However, the first tubular part, the second tubular part and the third tubular part are made individually so that it is necessary to provide airtight gaskets in the connecting portions of the first tubular part, the second tubular part and the third tubular part so as to prevent leakage, thereby increasing the cost of fabrication.
A conventional freeze safe valve comprises a valve body mounted between two pipes. The valve body has an interior provided with an elastic member, a water stop gasket, a water inlet disk, and a washer. A braking member is mounted between the elastic member and the water stop gasket. The water inlet disk has a periphery provided with water inlets holes. The water stop gasket is provided with a water inlet bore. In practice, when water passes the valve body, the water flows through the water inlets holes of the water inlet disk and the water inlet bore of the water stop gasket. On the contrary, when the water stops passing the valve body, the water stop gasket is pushed by the elastic member and the braking member to open vent holes that are connected to the interior of the valve body, so that the ambient air can enter the pipe to drain the water contained in the pipe. However, the conventional freeze safe valve only provides an automatic water draining device on the lower pipe, and the water will still stay in the upper pipe, so that the upper pipe is easily swollen and broken when the water freezes in the winter.